(a) Field of the Invention
The present invention relates to a shape calculation method of a spray head for painting which uniformly sprays paint onto the surface of a vehicle body and uniformly forms a painted surface to improve aesthetic characteristics of a vehicle body and maintain durability.
(b) Description of the Related Art
A technology using atomization of a liquid provides various benefits, e.g., the technology of a sprayer that sprays the liquid as very small particles can be used in different parts for various industries.
As a representative example, an atomization technology of the liquid is used as a primary technology in a fuel injection process and a painting process. As compared to other technologies, a rotary spraying method is advantageous in that fuel is sprayed by centrifugal force of a rotary shaft, and as a result, a device is stable while a load of the device is less subject to injection pressure, and a system structure is simple and allows for miniaturization. The advantage of the rotary fuel injection method provides the same advantageous method even in the case of painting.
An atomizer refers to a device that atomizes liquid to circularly spray the atomized liquid in a spray pattern and is rotated at high speed. The atomizer has an advantage in that all paint materials may be applied to the atomizer, and such a device is suitable for an environment requiring large-scale painting such as continuous vehicle painting and thus is continuously performed.
According to an injection principle, liquid painting is supplied to the center of a rotated disk to be dispersed and sprayed around by centrifugal force of the disk. In particular, when a rotational velocity and a liquid flow rate are controlled, a desired thickness of a liquid film may be obtained.
A bell cup may be fixed to the rotary shaft in a cone shape or a disk shape having a curve, and the paint is supplied to a back surface of the disk and thereafter, is spread outside the disk as a thin film by the centrifugal force of the disk that rotates at high speed.
In this case, the moment when the liquid deviates from the disk, the liquid is atomized by compressed air of a nozzle at an edge of the disk. A design of the spray head surface until the liquid is injected is the most important part in performance of the bell cup.
According to the design, painting quality is determined by the size of a liquid drop, and the size and the uniformity of the liquid drop depend on quality of a paint thin film formed on the surface of the bell cup by the centrifugal force.
The edge may have a plane shape, a single sawtooth shape, or a cross sawtooth shape according to a spray head shape. The spray head is used for various paints, and as a result, various models and transformed products are required to satisfy requirements of performance and quality.
Important elements to determine the required models or transformed products are a diameter of the spray head, a disk material, an operation RPM, and an angle of a spray head surface.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.